linux-kernel - [PATCH 06/11] vfs: factor out inode hash head calculation

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Message-ID: <20231206060629.2827226-7-david@fromorbit.com>
Date:   Wed,  6 Dec 2023 17:05:35 +1100
From:   Dave Chinner <david@...morbit.com>
To:     linux-fsdevel@...r.kernel.org
Cc:     linux-block@...r.kernel.org, linux-cachefs@...hat.com,
        dhowells@...hat.com, gfs2@...ts.linux.dev,
        dm-devel@...ts.linux.dev, linux-security-module@...r.kernel.org,
        selinux@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH 06/11] vfs: factor out inode hash head calculation

From: Dave Chinner <dchinner@...hat.com>

In preparation for changing the inode hash table implementation.

Signed-off-by: Dave Chinner <dchinner@...hat.com>
---
 fs/inode.c | 44 +++++++++++++++++++++++++-------------------
 1 file changed, 25 insertions(+), 19 deletions(-)

diff --git a/fs/inode.c b/fs/inode.c
index 3426691fa305..fead81550cf4 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -59,6 +59,22 @@ static unsigned int i_hash_shift __ro_after_init;
 static struct hlist_head *inode_hashtable __ro_after_init;
 static __cacheline_aligned_in_smp DEFINE_SPINLOCK(inode_hash_lock);
 
+static unsigned long hash(struct super_block *sb, unsigned long hashval)
+{
+	unsigned long tmp;
+
+	tmp = (hashval * (unsigned long)sb) ^ (GOLDEN_RATIO_PRIME + hashval) /
+			L1_CACHE_BYTES;
+	tmp = tmp ^ ((tmp ^ GOLDEN_RATIO_PRIME) >> i_hash_shift);
+	return tmp & i_hash_mask;
+}
+
+static inline struct hlist_head *i_hash_head(struct super_block *sb,
+		unsigned int hashval)
+{
+	return inode_hashtable + hash(sb, hashval);
+}
+
 /*
  * Empty aops. Can be used for the cases where the user does not
  * define any of the address_space operations.
@@ -502,16 +518,6 @@ static inline void inode_sb_list_del(struct inode *inode)
 		dlock_lists_del(&inode->i_sb_list);
 }
 
-static unsigned long hash(struct super_block *sb, unsigned long hashval)
-{
-	unsigned long tmp;
-
-	tmp = (hashval * (unsigned long)sb) ^ (GOLDEN_RATIO_PRIME + hashval) /
-			L1_CACHE_BYTES;
-	tmp = tmp ^ ((tmp ^ GOLDEN_RATIO_PRIME) >> i_hash_shift);
-	return tmp & i_hash_mask;
-}
-
 /**
  *	__insert_inode_hash - hash an inode
  *	@inode: unhashed inode
@@ -1187,7 +1193,7 @@ struct inode *inode_insert5(struct inode *inode, unsigned long hashval,
 			    int (*test)(struct inode *, void *),
 			    int (*set)(struct inode *, void *), void *data)
 {
-	struct hlist_head *head = inode_hashtable + hash(inode->i_sb, hashval);
+	struct hlist_head *head = i_hash_head(inode->i_sb, hashval);
 	struct inode *old;
 
 again:
@@ -1291,7 +1297,7 @@ EXPORT_SYMBOL(iget5_locked);
  */
 struct inode *iget_locked(struct super_block *sb, unsigned long ino)
 {
-	struct hlist_head *head = inode_hashtable + hash(sb, ino);
+	struct hlist_head *head = i_hash_head(sb, ino);
 	struct inode *inode;
 again:
 	spin_lock(&inode_hash_lock);
@@ -1359,7 +1365,7 @@ EXPORT_SYMBOL(iget_locked);
  */
 static int test_inode_iunique(struct super_block *sb, unsigned long ino)
 {
-	struct hlist_head *b = inode_hashtable + hash(sb, ino);
+	struct hlist_head *b = i_hash_head(sb, ino);
 	struct inode *inode;
 
 	hlist_for_each_entry_rcu(inode, b, i_hash) {
@@ -1446,7 +1452,7 @@ EXPORT_SYMBOL(igrab);
 struct inode *ilookup5_nowait(struct super_block *sb, unsigned long hashval,
 		int (*test)(struct inode *, void *), void *data)
 {
-	struct hlist_head *head = inode_hashtable + hash(sb, hashval);
+	struct hlist_head *head = i_hash_head(sb, hashval);
 	struct inode *inode;
 
 	spin_lock(&inode_hash_lock);
@@ -1501,7 +1507,7 @@ EXPORT_SYMBOL(ilookup5);
  */
 struct inode *ilookup(struct super_block *sb, unsigned long ino)
 {
-	struct hlist_head *head = inode_hashtable + hash(sb, ino);
+	struct hlist_head *head = i_hash_head(sb, ino);
 	struct inode *inode;
 again:
 	spin_lock(&inode_hash_lock);
@@ -1550,7 +1556,7 @@ struct inode *find_inode_nowait(struct super_block *sb,
 					     void *),
 				void *data)
 {
-	struct hlist_head *head = inode_hashtable + hash(sb, hashval);
+	struct hlist_head *head = i_hash_head(sb, hashval);
 	struct inode *inode, *ret_inode = NULL;
 	int mval;
 
@@ -1595,7 +1601,7 @@ EXPORT_SYMBOL(find_inode_nowait);
 struct inode *find_inode_rcu(struct super_block *sb, unsigned long hashval,
 			     int (*test)(struct inode *, void *), void *data)
 {
-	struct hlist_head *head = inode_hashtable + hash(sb, hashval);
+	struct hlist_head *head = i_hash_head(sb, hashval);
 	struct inode *inode;
 
 	RCU_LOCKDEP_WARN(!rcu_read_lock_held(),
@@ -1633,7 +1639,7 @@ EXPORT_SYMBOL(find_inode_rcu);
 struct inode *find_inode_by_ino_rcu(struct super_block *sb,
 				    unsigned long ino)
 {
-	struct hlist_head *head = inode_hashtable + hash(sb, ino);
+	struct hlist_head *head = i_hash_head(sb, ino);
 	struct inode *inode;
 
 	RCU_LOCKDEP_WARN(!rcu_read_lock_held(),
@@ -1653,7 +1659,7 @@ int insert_inode_locked(struct inode *inode)
 {
 	struct super_block *sb = inode->i_sb;
 	ino_t ino = inode->i_ino;
-	struct hlist_head *head = inode_hashtable + hash(sb, ino);
+	struct hlist_head *head = i_hash_head(sb, ino);
 
 	while (1) {
 		struct inode *old = NULL;
-- 
2.42.0